How to change the shape of a mesh object by handlers?
Update the mesh of the object, not of the evaluated object
As demonstrated here Updating objects parameters using python creates multiple objects
update the mesh of the object, not its evaluated (for that frame) object.
In addition do not mix context with handlers. The scene is passed as the first argument. This may or may not be the context scene when &quot;handled&quot;..
Only handle objects in the scene being handled..
ob = scene.objects.get(&quot;some_name&quot;)
if ob:
    ...

bpy.data.objects is a list of all objects in the blend file, which may or may not be linked to any scene, all scenes or none.
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How to get the updated vertex coordinates of a cube when rotating?